Organic Rankine cycles are considered a viable technology to convert low temperature waste heat to electricity. Yet, before large scale adoption can be seen, some hurdles need to be taken. First, the conversion efficiency should be raised further, especially for low temperatures (<200°C). Advanced ORC architectures have the ability to do this, as shown by many theoretical studies. However these new architectures are not commercialized. Even simulations based on more detailed semi-empirical models lack. Another challenge is the variability in time of the temperature and the capacity of the waste heat streams. To get a realistic picture of the power-output, part-load models are necessary. Preferably these models are validated on experimental set-ups. In this paper, validated part-load models from an 11 kWe ORC are used to analyse the optimal operating regime of the commercially available subcritical ORC (SCORC). As such the power output during varying load is optimized. Additionally, operation as a partially evaporating ORC (PEORC) is investigated. Depending on the operating regime the power output can be increased by 6% to 40% with a PEORC. Based on these preliminary results there are clearly opportunities available in retrofitting existing SCORCs to PEORC operation.

@inproceedings{7408904,
abstract = {Organic Rankine cycles are considered a viable technology to convert low temperature waste heat to electricity. Yet, before large scale adoption can be seen, some hurdles need to be taken. First, the conversion efficiency should be raised further, especially for low temperatures ({\textlangle}200{\textdegree}C). Advanced ORC architectures have the ability to do this, as shown by many theoretical studies. However these new architectures are not commercialized. Even simulations based on more detailed semi-empirical models lack. Another challenge is the variability in time of the temperature and the capacity of the waste heat streams. To get a realistic picture of the power-output, part-load models are necessary. Preferably these models are validated on experimental set-ups. In this paper, validated part-load models from an 11 kWe ORC are used to analyse the optimal operating regime of the commercially available subcritical ORC (SCORC). As such the power output during varying load is optimized. Additionally, operation as a partially evaporating ORC (PEORC) is investigated. Depending on the operating regime the power output can be increased by 6\% to 40\% with a PEORC. Based on these preliminary results there are clearly opportunities available in retrofitting existing SCORCs to PEORC operation.},
articleno = {295},
author = {Lecompte, Steven and van den Broek, Martijn and De Paepe, Michel},
booktitle = {29th International Conference on Efficiency, Cost, Optimization, Simulation and Environmental Impact of Energy Systems},
editor = {Kitanovski, Andrej and Poredo\v{s}, Alojz},
isbn = {978-961-6980-15-9},
keyword = {Organic Rankine cycle,ORC,Experimental,Optimal operation,Part-load},
language = {eng},
location = {Portoro\v{z}, Slovenia},
pages = {12},
title = {Optimal part-load operation of an 11 kWe organic Rankine cycle for waste heat recovery},
year = {2016},
}